Message-Id: <9405031639.AA14618@media.mit.edu>
Date: Tue, 3 May 94 12:37:53 EDT
From: "Chris Parker" <parker@VNET.IBM.COM>
To: FREDM@MEDIA.MIT.EDU

Using the Miniboard with PCBUG11...

PCBUG can be run on a 'standard' Miniboard if the RS232 level converters
are modified, but if the board does not need the motor drive interface
the following cost reductions can be made.

Eliminate 'ROBOTIC' Hardware:

Assemble the board, leaving out the following 'surplus' bits:
Inductors L1,L2 - replaced with wire jumpers, see below.
R PACS RP1, RP2, RP3
Resistors R1,R2,R3,R4,R5 (R5 will be replaced with jumper)
All the LEDs
74HC04 and its socket
L293Ds
The Pnp Tx
The 2 outboard rows of header pins at each port (outer row is Gnd, inner
        row is +5V at each port - useful for output devices)
The RS232 Jacks


Add the following wire jumpers:
Across L1's pins, and across L2's pins

Modify the RS232 circuitry (PCBUG doesn't work with the existing ckts).
Add the following wire jumpers:
74HC04  pin 12 to pin 13
Across space marked 'R5'
>From end of R4 immediately below '10K' on the sikscreen to the
4th pin of RP3 counting from the bottom of the card. (if these
components had been installed!).

Build a RS232<-> TTL converter, using a MAX232 & 4 caps as described
in Nuts & Volts (7/93 page 73), or the PCBUG manual Appendix A. Can be
built on a scrap of perfboard. Feed it with GND and +5 from any convenient
place on the miniboard. I use the blank header holes just above the 4pin
serial header.
More robust and reliable than the miniboards interface, and NEEDED for
duplex I/O.

Install a 4 pin hdr in the lower left corner where Fred has thoughtfully
brought the Tx/Gnd/Rx pins.

Make up a PC cable - only need the Txd, Rxd and Gnd lines, connect to the
4pin header.

========================================================================

** OPTIONAL ADDS ***

Install a 8 pin female hdr where RP2 would have gone.
Gives easy access to bits 2-5 of port D; 0 & 1 are at the 4pin Tx/RX header.
If E,R/W and AS are required wire pins 4,5 and 6 of the 52 pin socket to
the 4,5 and 2 pins of this header respectively, counting from the left.
The 8 pins are then (from the top left of the board):

Jumper the following pins:
L293D #1  pin 1 to 6, pin 2 to 11, pin 3 to 9, pin 14 to 15
L293D #2  pin 1 to 6, pin 2 to 14, pin 3 to 9, pin 10 to 11
This brings Port B directly to the 'motor' header.
Order is 0,1,4,5,2,3,6,7

So now we have ALL port pins brought out to headers.

========================================================================

Installing  the software:

I'm using PCBUG11 v3.24, had problems with 3.11.

Modify TALKEREE.ASC to 'ORG' at $F800 - and assemble.
Modify TALKEREE.MAP changing all $B6xx to $F8xx.

Put the Miniboard in Bootstrap mode (Switch to the right), and RESET.

Now run PCBUG using the -A option, verify it's working OK.

 PBBUG11 -A

If all's well do the following:
 MS $1035 0               Clear BPROT Reg
 EEPROM $F800 $F8FF       Allow programming of a chunk of EEPROM
 LOADS TALKEREE           Load the resident talker
 VERF TALKEREE            Verify the LOAD was OK.
 QUIT Y                   And quit.

Now restart PCBUG to use the talker:
PCBUG11 TALKEREE

The Talker MUST be named TALKEREE; the board stays in Bootstrap mode.

You have use of the RAM from $40 to $C3 for user programs, the stack is
already allocated from $00 to $3F by PCBUG, and the bootstrap pseudo
vectors are from $C4 to $FF. I usually debug small chunks of my programs,
then 'move' them to EEPROM.

Chris Parker (parker@vnet.ibm.com)